Ethics professor Jack Lambert's neighbor Max Mueller is revealed on the TV news to be escaped Nazi war criminal Karl Luger, whom the courts sentenced to death. Pressured by the news media's allegations, Mueller plans escape to South America.

Angered that Mueller might never pay for his crimes, Lambert takes the drastic step of poisoning him by injecting cyanide into some of the fruit in Mueller's apple tree, from which he regularly makes freshly juiced apple juice. The police initially believe it's a suicide, greatly upsetting Lambert, who mails them a cryptic letter explaining that it was actually a murder to carry out the court sentence and to avenge all the lives taken.

Later, the TV news reveals that Mueller was misidentified and is innocent. Feeling guilty, Lambert atones by dumping his fiancée Gail and marrying Mueller's daughter Inga. However, after the wedding, Lambert receives information assuring him of Mueller's guilt.